Typically to extrude bath surrounds or other parts, raw material is fed into a feed hopper which in turn provides a screw that passes from material through a heater. The material is pushed through a die and then may be pushed through coating equipment and extruded towards a trim knife. The cooling material is frequently passed through pull rollers.
Bath surrounds for tubs or for showers are usually one piece or several pieces. The one piece surrounds typically have two sidewalls and a back wall. Such one piece construction is problematic in that it is sometimes difficult to handle, difficult to get into a bathroom and expensive to ship because of the odd shapes that are not always nestable. They are also subject to damage while being handled.
To overcome these problems, surrounds may be created with three separate parts or two separate parts. The three part surrounds include a separate sidewall and a separate back portion. These walls can then be easily stacked and packed and shipping is easier as is placing the product into the bathroom for installation. However, many designs require that the corners be mated carefully such that leakage does not occur between or within seams between the sidewalls and the back wall. Also, caulk is usually used to seal the joints so that leakage does not get behind the walls thereof.
Bathing vessels may be manufactured from a variety of different materials, such as plastic materials. Plastic bathing vessels, however, must meet certain minimum performance requirements. For instance, the American National Standards Institute (ANSI) sets forth minimum physical requirements and testing methods for plastic bathtub and shower units. A bathing vessel that meets the requirements is approved for use in homes, buildings or other structures as a plumbing fixture.